1. Field of the Invention
The present invention relates to document management and more particularly to restricting access to electronic documents for different end users.
2. Description of the Related Art
Traditionally, documents have been exchanged between parties by way of hand delivery, postal service, or facsimile. More recently, the public Internet has become a highly effective medium through which electronic documents have been exchanged, particularly as attachments to electronic mail. Still, in many occasions, the use of electronic mail cannot provide an adequate medium for document transfer. Specifically, where the original copy of a document is in a hard copy format, with handwritten or non-textual elements, a facsimile device can be the preferred tool of document exchange.
Facsimile devices ordinarily exchange facsimile data with other facsimile devices over the public switched telephone network (PSTN). Specifically, as in the case of an ordinary telephone call, the calling facsimile device can establish a communicative link over the PSTN to a receiving facsimile device. Each of the devices can negotiate suitable data exchange protocols and the transfer of facsimile data can commence. Upon completion of the exchange, the received facsimile data can be transposed to hard copy form and the call can terminate. Of note, several technologies have been developed with which facsimile data can be exchanged between facsimile devices not over the PSTN, but over the public Internet. Referred to in the art as “IP faxing”, facsimile data can be packetized and forwarded across the Internet to a network node local to the facsimile recipient.
Whether by facsimile, e-mail attachment or other electronic mode of data transfer, distributing documents in many circumstances calls for the restriction of access to the document by particular individuals. In this regard, advanced forms of digital rights management (DRM) technologies provide for restrictions in accessing and re-distributing not only the content of an e-mail message or attachments thereto, but also individual files—especially word processing documents, spreadsheets and media files. These advanced DRM technologies, however, are reliant upon the electronic form of the sensitive content being restricted. Once the content has been reduced to print form, nothing restricts the subsequent scanning and transmitting or facsimile transmitting of an image of the sensitive content.